4 files changed, 43 insertions, 26 deletions

diff --git a/src/display.cc b/src/display.cc
index b0bc636..2059c9b 100644
--- a/src/display.cc
+++ b/src/display.cc
@@ -11,16 +11,8 @@ Display display;
 
 Display::Display()
 {
-	disp_buf[0] = 0xff;
-	disp_buf[1] = 0xfb;
-	disp_buf[2] = 0xdd;
-	disp_buf[3] = 0xfd;
-	disp_buf[4] = 0xdd;
-	disp_buf[5] = 0xfb;
-	disp_buf[6] = 0xff;
-	disp_buf[7] = 0xff;
 	char_pos = -1;
-	scroll_delay = 400;
+	update_delay = 400;
 }
 
 void Display::disable()
@@ -45,8 +37,6 @@ void Display::enable()
 void Display::multiplex()
 {
 	static uint16_t scroll;
-	uint8_t i, glyph_len;
-	uint8_t *glyph_addr;
 
 	/*
 	 * To avoid flickering, do not put any code (or expensive index
@@ -59,8 +49,17 @@ void Display::multiplex()
 	if (++active_col == 8)
 		active_col = 0;
 
-	if (++scroll == scroll_delay) {
+	if (++scroll == update_delay) {
 		scroll = 0;
+		need_update = 1;
+	}
+}
+
+void Display::update() {
+	uint8_t i, glyph_len;
+	uint8_t *glyph_addr;
+	if (need_update) {
+		need_update = 0;
 
 		for (i = 0; i < 7; i++) {
 			disp_buf[i] = disp_buf[i+1];
@@ -89,12 +88,25 @@ void Display::multiplex()
 
 void Display::reset()
 {
-	for (int i = 0; i < 8; i++)
+	for (uint8_t i = 0; i < 8; i++)
 		disp_buf[i] = 0xff;
 	str_pos = 0;
 	char_pos = -1;
 }
 
+void Display::setString(const char *new_str)
+{
+	setString((char *)new_str);
+}
+
+void Display::setString(char *new_str)
+{
+	reset();
+	for (uint8_t i = 0; new_str[i] != 0; i++) {
+		string[i] = new_str[i];
+	}
+}
+
 /*
  * Draws a single display column. This function should be called at least once
  * per millisecond.
diff --git a/src/display.h b/src/display.h
index 666648a..f48d1c3 100644
--- a/src/display.h
+++ b/src/display.h
@@ -6,18 +6,22 @@
 
 class Display {
 	private:
-		uint16_t scroll_delay;
+		uint16_t update_delay;
+		uint8_t need_update;
 		uint8_t active_col;
 		uint8_t disp_buf[8];
 		uint8_t str_pos;
 		int8_t char_pos;
+		char string[128];
 	public:
 		Display();
 		void enable(void);
 		void disable(void);
 		void multiplex(void);
 		void reset(void);
-		char string[128];
+		void update(void);
+		void setString(const char *str);
+		void setString(char *str);
 };
 
 extern Display display;
diff --git a/src/main.cc b/src/main.cc
index 9558109..4398d02 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -20,13 +20,7 @@ int main (void)
 	// Enable pull-ups on PC3 and PC7 (button pins)
 	PORTC |= _BV(PC3) | _BV(PC7);
 
-	display.string[0] = 'O';
-	display.string[1] = 'h';
-	display.string[2] = 'a';
-	display.string[3] = 'i';
-	display.string[4] = '!';
-	display.string[5] = ' ';
-	display.string[6] = 0;
+	display.setString("Ohai! ");
 
 	display.enable();
 	modem.enable();
@@ -37,9 +31,14 @@ int main (void)
 		// nothing to do here, go to idle to save power
 		SMCR = _BV(SE);
 		asm("sleep");
-		// The display timer causes a wakeup after 256µs. Run the system
-		// loop after the timer's ISR is done.
+		/*
+		 * The display timer causes a wakeup after 256µs. Run the system
+		 * loop after the timer's ISR is done.
+		 * The Modem also causes wakeups, which is pretty convenient since
+		 * it means we can immediately process the received data.
+		 */
 		rocket.loop();
+		display.update();
 	}
 
 	return 0;
diff --git a/src/system.cc b/src/system.cc
index 6c44a30..5c7b177 100644
--- a/src/system.cc
+++ b/src/system.cc
@@ -12,6 +12,8 @@
 
 System rocket;
 
+char disp_buf[128];
+
 void System::loop()
 {
 	static uint8_t i = 0;
@@ -70,12 +72,12 @@ void System::loop()
 
 	while (modem.buffer_available()) {
 		modem_char = modem.buffer_get();
-		display.string[i++] = modem_char;
+		disp_buf[i++] = modem_char;
 		if (i == 127) {
 			i = 0;
 		} else if (modem_char == 0) {
 			i = 0;
-			display.reset();
+			display.setString(disp_buf);
 		}
 	}
 }